In a blockchain-type ledger, a service provider can hardly modify data directly. However, there is still a possibility that a user or an enterprise and the service provider jointly falsify the data. Therefore, a user needs to perform time authentication on a ledger of the user to prevent fraud. Time authentication needs to be performed on multiple ledgers when there are many ledgers.
Based on this, a solution to perform time authentication in batches in a blockchain-type ledger is needed.